Field of the Invention
This application relates to a pharmaceutical preparation comprising a parasympathomimetic drug and an α1 (alpha1) adrenergic agonist or antagonist for ameliorating, reducing or treating presbyopia.
Description of the Related Art
Presbyopia is an age-related reduction in visual acuity due to a decline in near focusing ability, commonly associated with blurred appearance of objects at nearby distances. Symptoms of presbyopia often become noticeable by around age 40 to around age 45. Presbyopia is typically associated with the reduced accommodative ability of the eye. For example, flexibility or elasticity of the crystalline lens and strength of the ciliary muscles often decrease with age. A decrease in the flexibility or elasticity of the crystalline lens or the strength of ciliary muscles can be associated with a decrease in the ability of the eye in adjusting the curvature of the crystalline lens to focus on objects at nearby distances, including objects at around a normal reading distance.
Common treatments of presbyopia include use of eye glasses, such as reading glasses typically worn for near distance vision, and bi-focals or multi-focals to provide both improved near and distance vision for patients who already use correction for distance vision. Corrective contact lenses can also be used to treat presbyopia, including bi-focal, multi-focal or monovision contact lenses. Monovision contact lenses typically include a lens for distance vision in one eye, for example a dominant eye, and a lens for near distance vision in the other eye, for example a non-dominant eye. Surgical options are also available for treating presbyopia, including corrective eye surgery. For example, refractive eye surgery generally involves reshaping of the cornea. Refractive surgery can allow reshaping of the cornea in one eye while leaving the other eye untreated, for example correcting vision only in a non-dominant eye for improved near vision while allowing the dominant eye to maintain distance vision. Implantation of intraocular lenses (IOL) can be another surgical option in treating presbyopia, generally involving replacement of the natural lens with a synthetic one. However, eye glasses or corrective lenses may be cumbersome or provide inadequate treatment, while surgical correction can be invasive and are not without risks. Because these techniques merely compensate for the loss of accommodation by changing the way light enters the eye, patients would have to put on the glasses for near vision and remove the glasses for distance vision, or have only one eye corrected for near vision while the other eye remains uncorrected in order to maintain distance vision. Thus, a way to ameliorate or reduce the symptoms of presbyopia while allowing accommodation is needed.